Gold, structure

In any case, it is interesting to note that catalytic efficacy has been observed with nano- or mesoporous gold sponges [99-101, 145] suggesting that neither a discrete particle nor an oxide support is actually a fundamental requirement for catalysis. An alternative mechanism invokes the nanoscale structural effect noted in Section 7.2.2, and proposes that the catalytic effect of nanoscale gold structures is simply due to the presence of a large proportion of lowly-coordinated surface atoms, which would have their own, local electronic configurations suitable for the reaction to be catalyzed [34, 49,146] A recent and readily available study by Hvolbaek et al. [4] summarizes the support for this alternate view. 

Stokes, N., McDonagh, A. and Cortie, M.B. (2007) Application of nanolithography to the preparation of nanoscale gold structures. Gold Bulletin, 40, 310-320. 

Wallenberg, L.R., Bovin, J.O. and Schmid, G. (1985) On the crystal-structure of small gold crystals and large gold structures. Surface Science, 156, 256-264. 

Figure 9.6 Activity for CO oxidation at room temperature as a function of gold coverage on an Mo(l 12)—(8 x 2)-TiOx surface. The CO 02 ratio was 2 1 and the total pressure 5 Torr. Two discrete gold structures were investigated, (lxl) and (1 x 3). The initial turn over frequencies (TOF) over the (1 x 1) gold monolayer structure were significantly lower than that for the (1 x 3) bilayer structure. (Reproduced from Ref. 20).

C. K. In gold, Structure and Mechanism in Organic Chemistry, Bell, London, 1953, p. 785. 

Stark, R.W., Stalder, M.S., Stemmer, A., Microfluidic etching driven by capillary forces for rapid prototyping of gold structures. Microelectron. Eng. 2003, 67-68, 229-236. 

Fig. 11 Laterally gold structured silicon wafer to control the spatial adsorption of PVFA-co-PVAm (a) photograph of the gold structured silicon wafer (genuine size of the gold islands 45 pm by 45 pm), (b) spatially resolved XPS image of the lateral gold layer (the Au 4f peak is depicted in black whilst the peaks of O 1 s and Si 2p are pale), (c) spatially resolved XPS image of 11-mercaptoundecanoic acid adsorbed on the laterally structured gold layer (the S 2p peak is depicted in white whilst Si 2p is dark)...

The structure of alloys and structural changes at certain temperatures can explain the memory effect of special alloys (see E5.6) like Nitinol , a nickel-titanium alloy [4]. The structure as well as the much greater electric conductivity explains the difference between the copper-gold structures (CuAu and Cu3Au) and... 

An interesting feature concerning the redox properties of the complex, [Au(dddt)2] (dddt = 5,6-dihydro-l,4-dithiine-2,3-dithiolate, 3), is that the one-electron oxidized product, [Au(dddt)2]°, can be isolated14. An X-ray analysis of the neutral complex reveals a square planar gold structure stacked in dimeric units as a result of intermolecular S-----S contacts. Extended Hlickel calculations predict that the odd electron resides pri-... 

Fig. 6 Class C SPs. 14 Polyrotaxane " " 15 poly[2]catenane 18 linear dendritic hybrid chain from 7-oxanorbornene monomers substituted with two tapered monodentrons " and 20 SAMs of n-alkanethiolates on gold. Structures 16 [3]catenane and [3] rotaxane with two dibenzol[24]crown-8 rings 17 a-cyclodextrin 4-poly (ethylene oxide) and 19 tobacco mosaic virus are included for comparison.

Figure 6.40. Evolution ofsurface potential as a function of oxygen pressure (Imbar = 100 Pa) beta-alumina gold structure...

Meldmm, E., Seshadri, R. Porous gold structures through templating by ecbinoid skeletal plates. Chem. Commun. 29-30 (2000)... 

FIGURE 2 A representative photograph of a gold sample after dissolution of the latex. The highly ordered, lace-hke gold structure is an analogue of a 3D wire-mesh photonic crystal scaled down to the sub-micrometer region. SOURCE Adapted from Velev et al. (1999). Reprinted with permission from Nature. 

Non-chiral nanoparticles were also of interest for sensing of optical activity through the enhancement of the chirality of molecules in the presence of the plasmonic field at the edge of, for example nanocubes or gold structures on surfaces. ... 

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